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Proceedings Paper

Mapping of alpine grassland cover in western China from normalized Landsat TM image
Author(s): Yong Zha; Jay Gao
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Paper Abstract

Grassland cover near Lake Qinghai in western China was mapped into nine percentage classes from a TM-derived Normalised Difference Bareness Index (NDBI) image based on 178 in situ samples collected within 1 m2 sites. Their ground coordinates logged with a GPS unit were used to locate their pixel values on the NDBI image. A new method, in which the in situ samples and their pixel NDBI values were independently ranked prior to the establishment of their linear regression relationship, was applied to converting the NDBI image into a map of grass coverage. This relationship enabled the NDBI image to be translated into a map of grassland cover with a meaningful spatial pattern. Assessed against visually interpreted results, grassland cover was mapped at an overall accuracy of 80%. In order for this method to generate satisfactory results, image pixel NDBI values have to be normalized so that they have the same standard deviation as that of the ground samples. This proposed method should be applicable to any grassland where grassland cover varies subtly at the pixel scale of the image used.

Paper Details

Date Published: 25 April 2008
PDF: 8 pages
Proc. SPIE 7000, Optical and Digital Image Processing, 700023 (25 April 2008); doi: 10.1117/12.779146
Show Author Affiliations
Yong Zha, Nanjing Normal Univ. (China)
Jay Gao, Univ. of Auckland (New Zealand)


Published in SPIE Proceedings Vol. 7000:
Optical and Digital Image Processing
Peter Schelkens; Touradj Ebrahimi; Gabriel Cristóbal; Frédéric Truchetet, Editor(s)

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